How can I pass value from html input to javascript I have value_1 = 0 but when I change it in input form I want code inside if to happen.
<body>
<input type="number" name="a" id="commands"><br>
<canvas id="myChart1"></canvas>
<script>
const value_1 = 0;
const value_1 = document.getElementById("commands").value;
if(value_1 != 0)
{
//code
}
</script>
</body>
add a listener for the 'keyup' event, as follows:
document.getElementById("commands").addEventListener('keyup', (e) => {
let value = document.getElementById("commands").value;
if (value !== 0) {
// code
}
});
Or like this:
document.getElementById("commands").onkeyup = function(e) {
let value = document.getElementById("commands").value;
if (value !== 0) {
// code
}
}
or with jQuery:
$('#commands').on('keyup', (e) => {
let value = $('#commands').val();
if (value !== 0) {
// code
}
});
!== instead of !=You can use addEventListener with change event type or use the onchange property.
Example:
<script>
const value_1 = document.getElementById("commands");
value_1.onchange = function(){
if(value_1.value != 0)
{
console.log("Not 0");//code
}
}
</script>
If I understood,
To track input value changes you could do so by:
var inputValue = "";
document.getElementById("commands").addEventListener("keyup", function(event) {
inputValue = document.getElementById("commands").value;
// Here you can do anything, incase you need to have a callback whenever the value changes.
// Example:
if(inputValue != 0) {
// code.
}
});
You can pass value from html to JavaScript correctly using following code:
HTML:
<form onsubmit="return getValue('commands')">
<input type="number" name="a" id="commands">
<canvas id="myChart1"></canvas>
</form>
JavaScript:
<script>
function getValue(id) {
let value_1 = 0;
value_1 = document.getElementById(id).value;
alert(value_1);
if(value_1 != 0)
{
//code
}
return false;
}
</script>
const value_1 = 0;entirely because one line later you reassign the value ofvalue_1